/*
 * Copyright 2012-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.springcloud.gray.bean.properties.source;

import java.util.function.Predicate;

import org.springframework.util.Assert;

/**
 * The state of content from a {@link ConfigurationPropertySource}.
 *
 * @author Phillip Webb
 * @since 2.0.0
 */
public enum ConfigurationPropertyState {

    /**
     * The {@link ConfigurationPropertySource} has at least one matching
     * {@link ConfigurationProperty}.
     */
    PRESENT,

    /**
     * The {@link ConfigurationPropertySource} has no matching
     * {@link ConfigurationProperty ConfigurationProperties}.
     */
    ABSENT,

    /**
     * It's not possible to determine if {@link ConfigurationPropertySource} has matching
     * {@link ConfigurationProperty ConfigurationProperties} or not.
     */
    UNKNOWN;

    /**
     * Search the given iterable using a predicate to determine if content is
     * {@link #PRESENT} or {@link #ABSENT}.
     *
     * @param <T>       the data type
     * @param source    the source iterable to search
     * @param predicate the predicate used to test for presence
     * @return {@link #PRESENT} if the iterable contains a matching item, otherwise
     * {@link #ABSENT}.
     */
    static <T> ConfigurationPropertyState search(Iterable<T> source,
                                                 Predicate<T> predicate) {
        Assert.notNull(source, "Source must not be null");
        Assert.notNull(predicate, "Predicate must not be null");
        for (T item : source) {
            if (predicate.test(item)) {
                return PRESENT;
            }
        }
        return ABSENT;
    }

}
